Tracheal intubation involves the insertion of a hollow tubular device, known as a tracheal tube, into the trachea of a patient. The tube may be inserted through the mouth or, less desirably, the nose or may be inserted through the neck by way of an incision in the front of the throat. If inserted through the mouth or nose the tube is referred to as an endotracheal tube, if through the front of the throat the tube is referred to as a tracheostomy or trach tube. The two types of tubes will be referred to as tracheal tubes herein. The tracheal tube passes into the trachea and terminates at a position above the carina, anterior to a position between the second and fourth thoracic vertebrate. Gases may then be introduced through the central lumen of the tracheal tube and into the lungs of the patient.
The primary purpose of tracheal intubation is to mechanically ventilate the patient's lungs when the patient is incapable of normal breathing induced ventilation. Intubation may also be used to apply anesthetic gases during surgical intervention. It is desirable to seal the passageway around the tracheal tube in order to maintain enough air pressure to force the air into the lungs during mechanical ventilation and to prevent escape of gases past the tube (i.e. “short circuiting” or bypassing of the lungs). Such a seal may be produced by the use of an inflatable cuff or balloon surrounding the tracheal tube near its distal end. When the tracheal tube has been introduced into the patient's trachea, the inflatable cuff will normally be located about 3 to 5 centimeters above the carina and within the tube-like trachea.
Once inflated, the cuff will engage the wall of the trachea and thereby seal the trachea and prevent the gases being introduced through the tracheal tube from simply reversing course after exiting the distal end of the tube and traveling back up and around the tube to exit the mouth. While treatment of this sort has proved successful for patients having chronic or acute respiratory diseases, there is a constant risk of several complications.
One of the most common complications is known as ventilator associated (or acquired) pneumonia or VAP. Patients receiving tracheal intubation sometimes develop this pneumonia from an infection of the lungs, possibly induced by contaminated pooled secretions entering the trachea and the lungs after bypassing the epiglottis while intubated. The epiglottis normally operates as a valve which selectively closes the entry into the trachea and lungs to prevent the introduction of secretions and particulate matter. However, when a tracheal tube is in place, the epiglottis is held in an open position, and secretions which would normally be directed away from the trachea and into the digestive system instead follow the path of the tracheal tube and pool above the inflatable cuff.
One of the times of greatest risk of such infectious secretions reaching the lungs is upon the cessation of mechanical ventilation. In particular, when the need for tracheal intubation ends, the inflatable cuff of the tracheal tube is deflated so that the tracheal tube may be withdrawn from the patient. The infectious secretions which have pooled in the space above the inflatable cuff are then released and are free to flow into the lungs, where bronchitis or pneumonia may develop. There is also a risk of the infectious secretions reaching the lungs during the time the tracheal tube is in place by aspiration of the secretions that may leak past the tracheal tube cuff.
Removing these secretions from above the tracheal tube cuff would likely reduce the risk of such infections and tracheal tubes having inflatable cuffs and suction means are broadly known in the prior art. It is known, for example, to combine a single lumen suction tube with a tracheal tube. The suction tube provides means for constant suction or evacuation of any pooled secretions which accumulate in the trachea above the inflatable cuff. There remain a number of concerns with such prior art tubes, however. A single lumen for the suction tube under near constant suction often causes direct suction to be exerted on the tracheal mucosa, which may then result in damage to the mucosa. Another major problem with a single suction lumen is that it is also subject to clogging or occlusion, and as a result may be rendered completely useless. Secretions may be quite viscous and can block the opening of the suction lumen above the cuff (the suction port) or can travel into the suction lumen and build up on the inside walls to the point where flow in the lumen is stopped.
A number of attempts have been made to solve some of these problems. U.S. Pat. No. 4,305,392, for example, provides a tracheal tube having a suction lumen that terminates in a suction chamber in the shape of a bulge having four ports in order to avoid damaging the tracheal mucosa. U.S. Pat. No. 4,840,173 provides a suction tube with multiple openings which may be used to evacuate secretions that may pool above the inflatable cuff, again in the hope that the suction line will not adhere to the trachea. U.S. Pat. No. 5,143,062 discloses a double lumen through which air may be circulated, creating an indirect gentle suction through a suction eye communicating with the distal ends of the lumens. This design, however, does not provide adequate suction necessary for aspirating secretions and is easily occluded. US patent publication 2008/0121236 discloses a suction apparatus and connectors that allow a solution to be injected into a suction line. There is no mechanism in the '236 publication to allow the valve to return to a fail-safe or default position where suction is restored to the suction lumen after the user is finished using the apparatus.
The current solution to occlusion of the suction lumen is to remove the tracheal tube and replace it with another one, thus opening the system, or to dispense with suctioning the space above the cuff altogether. Clearly these solutions are unsatisfactory as they negate the purpose for having the suction lumen present. Dispensing with suctioning of secretions from the space above the cuff results in a buildup of such fluids and, when the tube is eventually removed, can allow the fluids present to flow into the lungs, possibly causing VAP. Removing the tube and replacing it involves opening the system and exposes the patient to all of the risks of intubation, low blood oxygen, irritation of the trachea and possible damage to the glottis, etc., as well as the movement of secretions from the space above the cuff to the lungs. Maintaining the patency of the tracheal tube can reduce or delay the risks of extubation, contributing to the likelihood of a successful outcome for the patient.
What is needed is a multilumen tracheal tube or catheter capable of suctioning secretions which have pooled in the space above the inflatable cuff in an effective manner, having a lumen and port that are capable of being cleaned of accumulated secretions without removal of the tube from the patient, so that the system may remain closed. It is also desirable that the system be simple, preferably intuitive, to operate, so that it may be used on a regular basis by nominally trained personnel. The instant disclosure addresses these problems by providing a multilumen tracheal tube and suction lumen system with a rinse function, having a valve that is straight-forward and easy to operate.